Radiation image sensor and scintillator panel

ABSTRACT

A radiation image sensor comprises (1) an image sensor 1 having a plurality of light receiving elements arranged one or two dimensionally, (2) scintillator  2  having columnar structure formed on the light-receiving surface of this image sensor  1  to convert radiation into light including wavelengths that can be detected by the image sensor  1 , (3) a protective film  3  formed so as to cover and adhere to the columnar structure of the scintillator  2 , and (4) a radiation-transmittable reflective plate  4  that has a reflective surface  42  disposed to face the image sensor across the protective film  3.

TECHNICAL FIELD

[0001] The present invention relates to an image sensor that detectsradiation images used in medical and other fields, as well as to ascintillator panel that converts radiation images to visible lightimages.

BACKGROUND ART

[0002] X-ray sensitive film has been used in X-ray imagingconventionally employed for medical and industrial purposes, butradiation imaging systems that use a radiation detecting element havebecome increasingly popular from the standpoint of convenience anddurability of the imaging result. In this type of radiation imagingsystem, two-dimensional image data derived from radiation is obtained aselectrical signals using a radiation detecting element having aplurality of pixels, these signals are processed by a processingapparatus and [the resulting image is] displayed on a monitor. Arepresentative radiation detecting element has a construction in whichscintillator is incorporated in light detectors arranged in a one or twodimensionally and incident radiation is converted into light by thisscintillator and detected.

[0003] CsI, which is a typical scintillator material, is amoisture-absorbing material that absorbs atmospheric water vapor(moisture) and dissolves. Because the characteristics of thescintillator, particularly the resolution, deteriorate as a result, thescintillator must have a construction whereby they are protected fromatmospheric moisture. As a construction whereby scintillator isprotected from atmospheric moisture, the technologies disclosed in JP05-196742A and in JP 05-242841A, as well as in International PublicationNos. WO-98/36290 and WO-98/36291 are known.

DISCLOSURE OF THE INVENTION

[0004] However, in the technologies disclosed in JP 05-196742A and in JP05-242841A, it is not easy to form the anti-moisture constructiondisclosed therein, and it is also difficult to ensure the durability ofthe construction. The technologies disclosed in InternationalPublication Nos. WO-98/36290 and WO-98/36291, on the other hand, solvethese problems, but particularly in order to limit radiation exposure tothe patient in a medical setting, a clear image must be obtained using asmall amount of radiation, and consequently there is a demand for aradiation image sensor and a scintillator panel by which a brightimaging result can be obtained.

[0005] Accordingly, an object of the present invention is to provide aradiation image sensor and a scintillator panel by which clearer outputimages can be obtained.

[0006] In order to achieve this object, the radiation image sensoraccording to the present invention is characterized in that it comprisesof (1) an image sensor comprising a plurality of light receivingelements arranged one or two dimensionally, (2) scintillator having acolumnar structure and formed on the light-receiving surface of thisimage sensor to convert radiation into light including wavelength bandsthat can be detected by this image sensor, (3) a protective film formedso as to cover the columnar structure of the scintillator and adherethereto, and (4) a radiation-transmittable reflective plate having areflective surface for the light from the scintillators and disposed toface the light-receiving surface of the image sensor across theprotective film.

[0007] On the contrast, the scintillator panel according to the presentinvention is characterized in that it comprises of (1) a substrate, (2)scintillator having a columnar structure and formed on this substrate toconvert radiation into light including wavelength bands that passthrough this substrate, (3) a protective film formed so as to cover thecolumnar structure of the scintillator and adhere thereto, and (4) aradiation-transmittable reflective plate having a reflective surface forthe light from the scintillator and dispose to face the substrate acrossthe protective film.

[0008] The radiation image sensor according to the present invention mayinclude this scintillator panel and a detector that detects the opticalimage that passes through the substrate.

[0009] In the scintillator panel and radiation image sensor according tothe present invention, because a protective film is formed so as tocover the scintillator and adhere thereto, the scintillator is wellprotected from atmospheric moisture. The scintillator converts radiationinto light including prescribed wavelength bands (here, such light isnot limited to visible light, but conceptually includes electromagneticwaves such as ultraviolet light, infrared rays or energy within aprescribed radiation spectrum), but part of the converted light isredirected to the incident surface that receives incident radiation.This redirected light returns to the scintillator via reflection fromthe surface of the protective film and reflection from the reflectivesurface of the reflective plate. As a result, a clear optical image isobtained. The reflectance of the reflective surface of the reflectiveplate is preferably high, but need not approach 100%. A reflectance ofseveral tens percent is sufficient.

[0010] It is preferred that the scintillator be formed so as to coverthe entire area of the surface on which the light receiving elements areformed as well as the periphery thereof, and it is also preferred thatthe reflective surface be located so as to cover the entire surface onwhich the scintillator is formed as well as the periphery thereof. Byforming the scintillator in this fashion, the light receiving elementslocated at the edges can be effectively used, and an effective number ofpixels can be ensured. If the reflective surface is located as describedabove, blurriness and a reduction in brightness around the scintillatorcan be reliably prevented.

[0011] It is preferred that the reflective plate comprise a metal plate.Alternatively, it is acceptable if the reflective plate includes aprotective film such as a metal film on the radiation-transmittablematerial. In this case, it is preferred that the radiation-transmittablematerial comprise a glass, resin or carbon-based plate. By using areflective plate having the construction described above, the reflectiveplate, the scintillator panel and the radiation image sensor can beeasily made, and sufficient performance of the reflective plate can beachieved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a cross-sectional view of a first embodiment of theradiation image sensor according to the present invention;

[0013]FIG. 2 is an expanded view of the area II indicated in FIG. 1;

[0014]FIG. 3 is a top view of the radiation image sensor shown in FIG.1;

[0015] FIGS. 4 to 6 are drawings to explain the manufacturing processfor the image sensor shown in FIG. 1;

[0016]FIG. 7 is a cross-sectional view of a second embodiment of theradiation image sensor according to the present invention;

[0017]FIG. 8 is an expanded view of the area VIII indicated in FIG. 7;

[0018]FIG. 9 is a cross-sectional view of a third embodiment of theradiation image sensor according to the present invention;

[0019]FIG. 10 is an expanded view of the area X indicated in FIG. 9;

[0020]FIG. 11 is a cross-sectional view of a first embodiment of thescintillator panel according to the present invention;

[0021]FIG. 12 is a summary drawing to explain a comparison experiment;

[0022]FIG. 13 is a cross-sectional view of the scintillator panelcomprising a comparison example used in the comparison experiment; and

[0023]FIG. 14 is an expanded view of the area XIV indicated in FIG. 12.

BEST MODE FOR CARRYING OUT THE INVENTION

[0024] The best mode for carrying out the present invention will beexplained in detail below with reference to the drawings. To facilitatethe comprehension of the explanation, the same reference numerals denotethe same parts, where possible, throughout the drawings, and a repeatedexplanation will be omitted. Furthermore, the dimensions andconfigurations shown in the drawings are not necessarily accurate ortrue to scale, and some parts may be enlarged in order to enable easierunderstanding.

[0025]FIG. 1 is a cross-sectional view of a first embodiment of theradiation image sensor according to the present invention, FIG. 2 is anexpanded view of a part thereof, and FIG. 3 is a top view thereof.

[0026] The solid imaging element 1 of this radiation image sensorcomprises a substrate 11 formed from an insulating material such asglass and a light receiving unit wherein light receiving elements 12that carry out photoelectric conversion are arranged two-dimensionallyon the substrate 11. These light receiving elements 12 compriseamorphous silicon diodes (PD) or thin film transistors (TFT).

[0027] Scintillator 2 having columnar structure to convert incidentradiation into light including wavelength bands that can be detected bythe light receiving elements 12 is formed on the light receiving unit ofthe solid imaging element 1. Here, ‘light’ is not limited to visiblelight, and conceptually includes electromagnetic waves that includeultraviolet light, infrared rays or energy within a prescribed radiationspectrum. It is preferred that the scintillator 2 be formed such thatthey cover the entire surface on which the light receiving elements 12are formed as well as the periphery thereof, as shown in FIGS. 1 and 3.The scintillator 2 may comprise various different materials, butTl-doped CsI that emits visible light with good photoemission efficiencyis preferred. The top of each columnar structures of scintillator 2 isnot flat, but is pointed upward, as shown in FIG. 2.

[0028] A protective film 3 is formed so as to cover each columnarstructure of scintillator transmittable 2, resides in the spacestherebetween, and adheres thereto. Accordingly, a fine pattern ofprotrusions and depressions is formed on the surface of the protectivefilm 3. It is preferred that this protective film 3 comprise a materialthat is transparent to X-rays and blocks water vapor, such aspolyparaxylylene resin (brand name ‘Parylene’, manufactured by ThreeBond), and particularly polyparachlorxylylene (brand name ‘Parylene C’,also manufactured by Three Bond). A coating of Parylene film offersexcellent characteristics as the protective film 3, such as extremelysmall moisture and gas permeability, a high level of water repellenceand chemical resistance, and superior electrical insulation performanceeven in a thin film, as well as transparency to radiation and visiblelight rays.

[0029] Details regarding Parylene coating are provided in ‘Three BondTechnical News’ (the Sep. 23, 1992 issue), and its characteristics willbe described here.

[0030] A Parylene coating can be applied via the chemical vacuumdeposition (CVD) method wherein the coating is applied in a vacuum to asupporting member in the same fashion as metal vacuum deposition. Thisprocess comprises a step of pyrolyzing a diparaxylylene monomer thatcomprises the raw material, and rapidly cooling the resulting substancein an organic solvent of toluene or benzene to obtain diparaxylylenereferred to as dimer, a step of pyrolyzing this dimer and generating astable radical paraxylylene gas, and a step of causing the generated gasto be adsorbed by and polymerize with a material to form apolyparaxylylene film having a molecular weight of approximately500,000.

[0031] There are two major differences between Parylene deposition andmetal vacuum deposition. First, when Parylene is deposited, the pressureis approximately 10-20 Pa, which is higher than the approximately 0.1 Paused during metal vacuum deposition, and secondly, the accommodationcoefficient for Parylene deposition is two to four digits lower than theaccommodation coefficient 1 for metal vacuum deposition. As a result,during deposition, the entire deposition material is first covered by amonomolecular film, and the Parylene is deposited on top of that film.Therefore, a film having no pinholes can be formed with a uniformthickness starting at 0.2 μm, and a coating can be applied to cornersand edge areas, as well as to gaps that have a width on the order ofmicrons and cannot be covered by a liquid coating. Furthermore, becauseheat processing is not necessary during the coating operation, which cantake place at a temperature close to room temperature, the process doesnot generate curing-induced mechanical stress or heat deformation, andoffers superior coating stability. Furthermore, coating can be appliedto most solid substances.

[0032] A reflective plate 4 comprising a radiation-transmittablematerial 41 coated with a reflective film 42 is placed on the protectivefilm 3 such that the surface of the reflective film 42 (i.e., thereflective surface) faces the protective film 3. Here, it is preferredthat the reflective surface run essentially parallel to thelight-receiving surface of the solid imaging element 1. Because thesurface of the protective film 3 has the fine protrusions anddepressions described above, gaps 5 are formed between the surface ofthe protective film 3 and the surface of the reflective plate 4 (i.e.,of the reflective film 42). The radiation-transmittable material 41 maycomprise a glass, polyvinyl or other resin, or carbon-based substrate.The reflective film 42 may comprise a metal film or a dielectricmulti-layer film formed through deposition, and in the case of a metalfilm, it is preferred that such film comprise aluminum deposition filmor other film having a high light reflectance.

[0033] The reflective plate 4 is fixed to the surface of the solidimaging element 1 by a frame 6. The frame 6 comprises three layers 6 athrough 6 c arranged in that order from the side nearest the solidimaging element 1. The protective film 3 is sandwiched between the firstlayer 6 a and the second layer 6 b, such that the protective film 3 isfixed by its own edges. It is preferred that this frame 6 compriseKJR651 or KE4897 silicon resin manufactured by Shinetsu Chemical, TSE397silicon resin manufactured by Toshiba Silicon, or DYMAX625T siliconresin manufactured by Sumitomo 3M. These materials are widely used insurface processing to provide mechanical or electrical protection forsemiconductor elements, and offer tight adhesion to the protective film3. Alternatively, a resin having good adhesion to the protective film 3such as World Rock No. 801-Set 2 acrylic adhesive (70,000 cP type)manufactured by Kyoritsu Chemical Mfg. Co., Ltd. may be used. This resinadhesive has desirable characteristics: it cures in approximately 20seconds upon the irradiation of 100 mW/cm² ultraviolet light, theeffective coating is flexible and sufficiently strong, offers superiorresistance to moisture, water, electrical corrosion and migration, andhas good adhesion characteristics, particularly in regard to glass andplastic. On the other hand, appropriate materials may be selectedindividually for each layer and combined: a frame formed of asemiconductor substance, ceramic, metal, glass or the like may be usedfor the first layer 6 a and the second layer 6 b instead of a resinframe, or the first layer 6 a itself may be integrally formed with thesolid imaging element 1.

[0034] The making process of this embodiment will now be explained withreference to FIGS. 1 through 6. First, as shown in FIG. 4, scintillator2 is formed on the light-receiving surface of the solid imaging element1 (the side on which the light receiving elements 12 are formed) bygrowing columnar crystal of Tl-doped CsI to a thickness of 600 μm viathe deposition method. When this is done, it is preferred that thescintillator 2 be grown such that they cover the part on which the lightreceiving elements 12 are formed and extend as far as the peripherythereof.

[0035] Subsequently, after the solid imaging element 1 on which thescintillator 2 is deposited undergoes annealing at 200-210° C., UV-curedresin is applied in a frame configuration around the scintillator 2, andthe resin is cured through the irradiation of UV light to form the firstlayer 6 a of the resin frame 6. An automatic X-Y coating apparatus suchas the AutoShooter 3 made by Iwashita Engineering, for example, may beused during this frame formation. It is preferred that the surface ofthe resin frame 6 undergo roughness processing during this formationoperation in order to improve adhesion to the protective film 3 formedon the top thereof. Such roughness processing may comprise the formationof lines or numerous small depressions.

[0036] The CsI that forms the scintillator 2 is highlymoisture-absorbent, and if exposed to the atmosphere as is, absorbsatmospheric water vapor and dissolves. Accordingly, in order to preventthis, Parylene is deposited to a thickness of 10 μm using the CVD methodso as to cover the solid imaging element 1, thereby forming a protectivefilm 3. Gaps are formed between the columnar crystals of CsI as shown inFIG. 2, but the Parylene enters these narrow gaps. As a result, aprotective film 3 is formed on the scintillator 2 while adheringthereto. Furthermore, as a result of this Parylene coating, a fine thinfilm coating having an essentially uniform thickness is obtained on thesurface of the scintillator 2 having protrusions and depressions.Moreover, because forming the Parylene coating via the CVD methodrequires less of a vacuum than metal deposition and can be performed atroom temperature, processing is easy.

[0037] The protective film 3 formed as described above is then cut alongthe length of the first layer 6 a of the resin frame 6 using a cutter.Because protrusions are formed by the first layer 6 a of the resin frame6, it is easy to determine the cutting location, and because there is amargin equivalent to the thickness of the first layer 6 a of the resinframe 6 when the cutter is inserted, there is no danger of damaging thesolid imaging element 1 located below the resin frame 6, making processsimpler and improving the manufacturing yield. The protective film 3that is formed outside the cutting area and on the side opposite theincident light surface is then removed. FIG. 5 shows the situation whenthe protective layer 3 is formed in this fashion.

[0038] The second layer 6 b of the resin frame 6 is then formed as shownin FIG. 6 by applying acrylic resin to cover the edges of the protectivelayer 3 and the exposed first layer 6 a of the resin frame 6 and curingresin via UV irradiation. When this is done, the second layer 6 b isformed to a height that is approximately 0.5 mm higher than the topsurface of the scintillator 2.

[0039] By sandwiching the protective film 3 between the first layer 6 aand second layer 6 b of the resin frame 6 in this fashion, the adhesionof the protective film 3 over the solid imaging element 1 is furtherimproved, which is desirable. As a result, because the scintillator 2 iscompletely closed off by the protective film 3, moisture can be reliablyprevented from coming into contact with the scintillator 2, and adecrease in resolution of the solid imaging element 1 due tomoisture-absorption based deterioration in the scintillator 2 can beprevented.

[0040] Next, a reflective plate 4 comprising a radiation-transmittablematerial 41, which is a 0.4 mm-thick glass plate, and a reflective film42 formed on one surface thereof by vapor deposition of aluminum to a1000 Å thickness, is placed on the solid imaging element 1 such that thereflective surface thereof, i.e., the surface on which the reflectivefilm 42 is formed, faces the protective film 3. In other words, thereflective surface is placed such that it faces the light-receivingelements 12. When this is done, it is preferred that the light-receivingsurface of the solid imaging element 1 and the reflective surface of thereflective film 42 run essentially parallel to each other, and that theprotective film 3 and the reflective film 42 be located such that theyare in contact or in close proximity to each other. A third layer 6 c isformed by applying UV-cured resin between the reflective plate 4 and thesecond layer 6 b of the resin frame 6 and curing the resin through theirradiation of UV light, whereby the reflective plate 4 is fixed to thesolid imaging element 1. The radiation image sensor of this embodimentshown in FIG. 1 is obtained in this fashion.

[0041] Here, the TN-cured resin need not be applied to the entire areaof the reflective plate 4, and it is sufficient so long as the amountnecessary to fix the reflective plate 4 is applied. For example, asshown in FIG. 3, it is acceptable if the UV-cured resin is not appliedto parts of the side of the solid imaging element 1 on which electrodes13 are not formed, and if openings 51 are present that connect theinterior spaces 5 and the external space. When openings 51 are presentas described above, even where thermal processing is applied to theradiation image sensor after fixing of the reflective plate 4, or whereit is used in an environment subject to fluctuations in temperature,deformation in the reflective plate 4 or in the radiation image sensoritself due to expansion or contraction of the air inside the interiorspaces 5 can be prevented.

[0042] The operation of this embodiment will now be explained. TheX-rays (radiation) that strike the incident light surface, i.e., the topsurface in FIG. 1 and FIG. 2, pass through the reflective plate 4 (theradiation-transmittable material 41 and the reflective film 42), thespaces 5 and the protective film 3, and reach the scintillator 2. TheseX-rays are absorbed by the scintillator 2, and visible light rays areemitted in proportion to the amount of X-rays. Part of the emittedvisible light rays that are redirected toward the X-ray incidencedirection are reflected at the boundary surface of the protective film 3and return to the scintillator 2. The visible light released through theprotective film 3 is reflected by the reflective film 42 and returns tothe scintillator 2. As a result, almost all of the visible light emittedby the scintillator 2 enters the light receiving elements 2.Consequently, efficient, high-sensitivity measurement can be performed.

[0043] Electrical signals corresponding to the amount of visible lightare generated by each light receiving element 2 via photoelectricconversion and are accumulated at fixed intervals. Because the amount ofvisible light corresponds to the amount of incident X-ray radiation, theelectrical signals accumulated in each light receiving element 2correspond to the amount of incident X-ray radiation, and an imagesignal corresponding to the X-ray image is obtained. The image signalsaccumulated in the light receiving elements 2 are transmittedexternally, and through processing of these image signals via aprescribed processing circuit, an X-ray image can be displayed.

[0044] A second embodiment of the radiation image sensor according tothe present invention is shown in FIG. 7 and FIG. 8. This radiationimage sensor uses a metal plate 4 a as the reflective plate instead ofthe reflective plate 4 of the first embodiment shown in FIGS. 1 and 2.For this metal plate 4 a, an aluminum sheet having a thickness ofapproximately 0.05 mm, for example, may be used. The use of this type ofmetal plate 4 a enables the apparatus to be made thinner.

[0045] A third embodiment of the radiation image sensor according to thepresent invention is shown in FIG. 9 and FIG. 10. While the radiationimage sensor in the first embodiment shown in FIGS. 1 and 2 was placedsuch that it was in contact with or in very close proximity to theprotective film 3, in this radiation image sensor, there is asubstantial distance between the reflective plate 4 and the protectivefilm 3. Spacers 7 are used to place the reflective plate 4 at a distancefrom the protective film 3. Naturally, it is acceptable if thereflective plate 4 has separation distance by increasing the height ofthe resin frame 6, without using spacers 7. The space 5 a created byseparating the reflective plate 4 from the protective film 3 may be madea layer of air or filled with a particular gas, or may be depressurizedor made a vacuum.

[0046]FIG. 11 is a cross-sectional view of a first embodiment of thescintillator panel according to the present invention. This scintillatorpanel uses a translucent substrate 1 a instead of the solid imagingelement 1 of the radiation image sensor shown in FIGS. 1 and 2, but isotherwise identical thereto. For the translucent substrate la, a glassplate or a resin such as acrylic or the like may be used. Theconstruction and placement of the reflective plate shown in FIGS. 7through 10 may be applied to the scintillator panel shown in FIG. 11.The radiation image sensor according to the present invention can beconstructed through the combination of this scintillator panel with atelevision camera or the like.

[0047] Because the inventors have carried out comparison experimentsthat confirm that images brighter than those obtainable with theconventional art can be obtained using the scintillator panel accordingto the present invention, the results of such experiments will beexplained below.

[0048]FIG. 12 is a drawing showing the basic construction of theexperiment apparatus. In this experiment, after scintillator was formedby depositing a 600 μm-thick layer of Tl-doped CsI on a 1 mm-thicksquare glass plate having sides 65 mm in length and a protective film ofParylene was created, eight types of scintillator panels havingdifferent constructions for the reflective film and the like werecreated. Subsequently, after radiation emitted from an X-ray tube towhich a peak voltage of 80 kV was impressed was guided to the testedarticle, i.e., the scintillator panel 100, via a 20 mm-thick Al filter,and the visible light image generated by the scintillator panel 100 wasguided to a CCD camera 102 by a 28 mm lens 101, the optical outputintensity, which as a practical matter is the intensity of the outputelectrical signals from the CCD camera 102, was measured by a detector103.

[0049] The following eight types of scintillator panels were used in thecomparison experiments. First, the example 1 had the configuration shownin FIG. 8, and for the metal plate 4 a, a 0.05 mm-thick aluminum sheetmanufactured by Toyo Metallizing was used. The examples 2 through 5 allhad the configuration shown in FIG. 2, and an aluminum deposited filmwas used as the reflective film 42. The radiation-transmittable material41 used in the example 2 was a 0.4 mm glass plate, and the thickness ofthe reflective film 42 was 1000 angstroms. The radiation-transmittablematerial 41 used in the examples 3 and 4 was a 0.5 mm vinyl chlorideplate, and the thickness of the reflective film 42 was 400 angstroms and1000 angstroms, respectively. The radiation-transmittable material 41used in the example 5 was a 0.5 mm carbon-based substrate, and thethickness of the protective film 42 was 1000 angstroms. Theconstructions used in the examples 6 and 7 were those shown in FIGS. 9and 10, and the construction of the reflective plate 4 used therein wasidentical to that used in the example 4. In addition, the protectivefilm 3 and the reflective film 42 were separated by 1.5 mm in theexample 6 and by 2.5 mm in the example 7.

[0050]FIGS. 13 and 14 are drawings showing the construction of thecomparison example. This comparison example is equivalent to thescintillator construction disclosed in International Publication No.W098/36290, and differs from the examples in that an aluminum depositedfilm 8 is formed on the protective film 3.

[0051] The amount of light increase obtained in each example relative tothe comparison example is shown in the table 1 below. TABLE 1 Increasein light amount in each example relative to comparison example ExampleAmount of light 1 +38% 2 +36% 3 +18% 4 +38% 5 +36% 6 +26% 7 +19%

[0052] In each example, the amount of light increased relative to thecomparison example, and a bright image could be obtained. This thoughtto be due to the fact that according to the present invention, it iseasy to make the reflective surface flat and sufficiently thick, thedispersion in unnecessary directions by the reflective surface isreduced by keeping the reflective surface parallel to the optical imageoutput surface of the scintillator, the amount of reflected light due tothe reflection by the boundary surface between the protective surfaceand the spaces increased, etc.

[0053] Industrial Applicability

[0054] The radiation image sensor or scintillator panel according to thepresent invention can be advantageously applied in X-ray imaging forindustrial or medical purposes.

1. A radiation image sensor comprising: an image sensor having aplurality of light receiving elements arranged one or two dimensionally;scintillator having columnar structure and formed on the light-receivingsurface of said image sensor to convert radiation into light includingwavelength bands that can be detected by said image sensor; a protectivefilm formed so as to cover and adhere to said columnar structure of thescintillator; and a radiation-transmittable reflective plate having areflective surface for the light from the scintillator and disposed toface the light-receiving surface of the image sensor across saidprotective film.
 2. The radiation image sensor according to claim 1,characterized in that said scintillator is formed so as to cover theentire surface of the light receiving elements of said image sensor aswell as the periphery thereof.
 3. The radiation image sensor accordingto claim 1 or claim 2, characterized in that said reflective surface isdisposed so as to cover the entire surface on which said scintillator isformed as well as the periphery thereof.
 4. The radiation image sensoraccording to any of claims 1 to 3, characterized in that said reflectiveplate is a metal plate.
 5. The radiation image sensor according to anyof claims 1 to 3, characterized in that said reflective plate has areflective film formed on a radiation-transmittable material.
 6. Theradiation image sensor according to claim 5, characterized in that saidradiation-transmittable material is a glass, resin or carbon-basedsubstrate.
 7. The radiation image sensor according to claim 5 or 6,characterized in that said reflective film is a metal film.
 8. Ascintillator panel comprising: a substrate; scintillator having columnarstructure formed on said substrate and convert radiation into lightincluding wavelength bands that pass through said substrate; aprotective film formed so as to cover and adhere to said columnarstructure of the scintillator; and a radiation-transmittable reflectiveplate having a reflective surface for the light from the scintillatorand disposed to face the substrate across said protective film.
 9. Thescintillator panel according to claim 8, characterized in that saidreflective surface is disposed so as to cover the entire surface onwhich said scintillator is formed as well as the periphery thereof. 10.The scintillator panel according to claim 8 or 9, characterized in thatsaid reflective plate is a metal plate.
 11. The scintillator panelaccording to claim 8 or 9, characterized in that said reflective platehas a reflective film formed on a radiation-transmittable material. 12.The scintillator panel according to claim 11, characterized in that saidradiation-transmittable material is a glass, resin or carbon-basedsubstrate.
 13. The scintillator panel according to claim 11 or 12,characterized in that said reflective film is a metal film.
 14. Aradiation image sensor comprising a scintillator panel according to anyof claims 8 to 13 and a detector that detects optical images that havepassed through said substrate.